and the waters are more acidic. >> this is a very dramatic change that has not been seen in the worlds oceans for more than 50 million years. >> woodruff: mark shields and david brooks analyze the week's news. >> brown: and gwen ifill sits down with michael beschloss, whose recent foray into the twitter-verse has opened up a new way to view history in the digital age. >> woodruff: that's all ahead on tonight's "newshour." major funding for the pbs newshour has been provided by: and with the ongoing support of these institutions and foundations. and... this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. >> brown: more people found work in november and more people stopped looking for work. as a result, the number of new jobs came in better than expected today and the rate of unemployment was the lowest since 2008. "newshour" economics correspondent paul solman begins our coverage. >> reporter: washington brightened yesterday when the annual switch was flipped; the white house christmas tree, relit.